Door knob door stop



FIG. 1 is a perspective view of a door knob door stop, showing my new design;

FIG. 2 is a side elevational view thereof, the other sides being identical;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a bottom view thereof. 

The ornamental design for a door knob door stop, as shown and described. 